482 LOEANDE LOSS WOODRUFF AND RH. ERDMANN 



the general physiological activities of the cells, and interpreted 

 as the result of relatively slight disturbances of the nuclear con- 

 dition which were overcome by internal readjustment. In the 

 periods of deep depression, on the other hand, marked signs 

 of degeneration were evident, for which the sole panacea was 

 conjugation. This led Hertwig to the natural suggestion that 

 the nuclear phenomena observed in physiological depression and 

 those which occur at conjugation have fundamentally the same 

 raison d'etre. 



Calkins ('04, p. 424) in his studies on Paramaecium caudatum 

 noted that the well-marked cycles which resulted in death, unless 



mijtl^m ffhfh 



m 



fr 



rocess 



Text fig. 18 Diagram illustrating the relation of the reorganization process 

 to rhythms. 



drastic methods of artificial stimulation were resorted to, were 

 of about six months duration, while intermediate cycles of less 

 importance occurred at intervals of approximately ninety days, 

 recovery from which took place without purposeful stimulation. 

 In these smaller cycles morphological signs of degeneration were 

 not observed, but in the well-marked cycles cytoplasmic and 

 nuclear changes occurred. These varied somewhat in character 

 at the low points of the various cycles, but in several instances 

 Calkins was able to restore the normal condition by the oppor- 



